Anger often acts as a pressure gauge for stress you haven't been able to...

https://sierra-wiki.win/index.php/Why_You%E2%80%99re_Snapping:_The_Real_Reason_Sleep_Deprivation_and_Irritability_Go_Hand-in-Hand

Anger often acts as a pressure gauge for stress you haven't been able to release. When it builds up, you might notice a tight jaw or shoulders that never seem to drop. You might even find yourself staring at the ceiling when you need sleep most